The present invention relates to a ferrule for a fitting for a fluidic device.
In liquid chromatography, a fluidic phase containing a fluidic analyte may be pumped through a column comprising a material which is capable of separating different components of the fluidic analyte. Such a material, so-called beads which may comprise silica gel that can be chemically modified, may be filled into a column tube which may be connected to other elements (like a control unit, containers including sample and/or buffers). During operation, such columns may be subjected to high pressures of, for instance, up to 600 bar (60 MPa, or about 8,702 pounds per square inch) and more. The liquid chromatographic process includes mixing of the fluidic phase and analyte and introducing this mixture into the column tube with a continuous flow. The different solutes within the sample interact differently with the silica gel in the column and thus move at different speeds through the column resulting in separations of the solutes. The separated solutes may then be detected by various detectors.
In gas chromatography, solutes or components of an analyte sample are separated. Generally, a gas chromatography device includes a downstream column system, including one or more capillary columns for separating the solutes. The columns are typically made of metal, glass or quartz with a thin-film coating or stationary phase which may be connected to other elements (like a pressure control unit, gas supply units and sample containers). The gas chromatography process includes mixing the analyte sample with a carrier gas, such as hydrogen or helium, and introducing the sample/carrier gas mixture into the column(s) using a continuous flow. Various solutes within the sample interact differently with the stationary phase, and thus move at different speeds through the column(s), resulting in separation of the solutes. The separated solutes may then be detected by various detectors or provided as input to a mass spectrometer device, for example.
Fittings for coupling different components, such as separation columns and conduits, of fluidic devices, such as gas chromatography devices or liquid chromatography devices, are commercially available and are offered, for instance, by the company Swagelok (see for instance http://www.swagelok.com).
Conventionally, multiple ferrule systems (for instance U.S. Pat. No. 7,108,288, U.S. Pat. No. 7,367,595, US 2009/0295156, U.S. Pat. No. 7,735,878) are used. Single ferrule systems (for instance U.S. Pat. No. 6,056,331, U.S. Pat. No. 5,669,637, U.S. Pat. No. 6,575,501, U.S. Pat. No. 7,316,777, WO 2012/009726, U.S. Pat. No. 3,893,716, U.S. Pat. No. 4,205,417, U.S. Pat. No. 4,586,731, U.S. Pat. No. 6,926,313, U.S. Pat. No. 7,066,496, U.S. Pat. No. 8,038,180, US 2008/0054626, U.S. Pat. No. 6,131,963, U.S. Pat. No. 6,629,708) can be used to simplify the design.
Specifically, connection systems for glass capillaries as used in gas chromatography are disclosed in, U.S. Pat. No. 8,128,131 and WO 2001/73338.
For making a leak-free connection, a ferrule may be used together with a corresponding nut or housing. Such systems are disclosed in U.S. Pat. No. 5,595,406, U.S. Pat. No. 6,102,449, U.S. Pat. No. 5,540,464, U.S. Pat. No. 5,288,113.
There are tough requirements regarding sealing performance and mechanical stability of a fitting of fluidic measurement devices.